Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located in between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer.
The absorbent core can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the tradename HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body fluid.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators may include alarm devices that are designed to assist parents or attendants identify a wet diaper condition early on. The devices can produce an audible signal.
In the past, for instance, wetness indicators have included an open circuit incorporated into the absorbent article that is attached to a power supply and an alarm device. When a conductive substance, such as urine, is detected in the absorbent article, the open circuit becomes closed causing the alarm device to activate. The open circuit may comprise, for instance, two conductive elements that may be made from a metal wire or foil.
Problems have been experienced, however, in efficiently and reliability incorporating wetness indicators into absorbent articles at the process speeds at which absorbent articles are produced. Thus, a need exists for improved wetness sensors that can be easily incorporated into absorbent articles.
In addition, a need also exists for conductive elements for use in a wetness indicator that are made from non-metallic materials. Incorporating metallic components into an absorbent article, for instance, may cause various problems. For instance, once the absorbent articles are packaged, the absorbent articles are typically exposed to a metal detector to ensure that no metallic contaminants have accidentally been included in the package. Making the conductive elements of a wetness indicator from a metal, however, may cause a metal detector to indicate a false positive. The incorporation of metal conductive elements into an absorbent article may also cause problems when the wearer is attempting to pass through a security gate that also includes a metal detector.